Toshiba Satellite l640 sound not working on Windows 7 64 bit

So the Sound was not working on my Toshiba Satellite, this happened after I installed the MTNL 3g HSDPA.
Thought it was driver issue but then why did it happen after I installed MTNL 3G, Weird.

Anyways after a bit of googling I figured it out.

Open the Start Menu in search type Sound and then click on change system sounds.
Next click on the Playback Tab and select Speakers High Definition audio device and the click on default and thats it, the speaker sound started working.

It turns out that the HSDPA was selected as default sound Device and hence the speakers were not working 🙂